| Preface | xv |
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| 1. | Introduction
Sample Chapter - Download PDF (381 KB) | 1 |
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| 1.1 | Neurons | 1 |
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| 1.1.1 | What Is a Spike? | 2 |
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| 1.1.2 | Where Is the Threshold? | 3 |
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| 1.1.3 | Why Are Neurons Different, and Why Do We Care? | 6 |
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| 1.1.4 | Building Models | 6 |
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| 1.2 | Dynamical Systems | 8 |
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| 1.2.1 | Phase Portraits | 8 |
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| 1.2.2 | Bifurcations | 11 |
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| 1.2.3 | Hodgkin Classification | 14 |
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| 1.2.4 | Neurocomputational properties | 16 |
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| 1.2.5 | Building Models (Revisited) | 20 |
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| Review of Important Concepts | 21 |
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| Bibliographical Notes | 21 |
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| 2. | Electrophysiology of Neurons | 25 |
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| 2.1 | Ions | 25 |
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| 2.1.1 | Nernst Potential | 26 |
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| 2.1.2 | Ionic Currents and Conductances | 27 |
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| 2.1.3 | Equivalent Circuit | 28 |
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| 2.1.4 | Resting Potential and Input Resistance | 29 |
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| 2.1.5 | Voltage-Clamp and I-V Relation | 30 |
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| 2.2 | Conductances | 32 |
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| 2.2.1 | Voltage-Gated Channels | 33 |
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| 2.2.2 | Activation of Persistent Currents | 34 |
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| 2.2.3 | Inactivation of Transient Currents | 35 |
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| 2.2.4 | Hyperpolarization-Activated Channels | 36 |
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| 2.3 | The Hodgkin-Huxley Model | 37 |
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| 2.3.1 | Hodgkin-Huxley Equations | 37 |
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| 2.3.2 | Action Potential | 41 |
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| 2.3.3 | Propagation of the Action Potentials | 42 |
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| 2.3.4 | Dendritic Compartments | 43 |
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| 2.3.5 | Summary of Voltage-Gated Currents | 44 |
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| Review of Important Concepts | 49 |
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| Bibliographical Notes | 50 |
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| Exercises | 50 |
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| 3. | One-Dimensional Systems | 53 |
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| 3.1 | Electrophysiological Examples | 53 |
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| 3.1.1 | I-V Relations and Dynamics | 54 |
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| 3.1.2 | Leak + Instantaneous INa, p | 55 |
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| 3.2 | Dynamical Systems | 57 |
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| 3.2.1 | Geometrical Analysis | 59 |
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| 3.2.2 | Equilibria | 60 |
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| 3.2.3 | Stability | 60 |
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| 3.2.4 | Eigenvalues | 61 |
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| 3.2.5 | Unstable Equilibria | 61 |
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| 3.2.6 | Attraction Domain | 62 |
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| 3.2.7 | Threshold and Action Potential | 63 |
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| 3.2.7 | Threshold and Action Potential | 63 |
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| 3.2.8 | Bistability and Hysteresis | 66 |
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| 3.3 | Phase Portraits | 67 |
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| 3.3.1 | Topological Equivalence | 68 |
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| 3.3.2 | Local Equivalence and the Hartman-Grobman Theorem | 69 |
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| 3.3.3 | Bifurcations | 70 |
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| 3.3.4 | Saddle-Node (Fold) Bifurcation | 74 |
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| 3.3.5 | Slow Transition | 75 |
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| 3.3.6 | Bifurcation Diagram | 77 |
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| 3.3.7 | Bifurcations and I-V Relations | 77 |
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| 3.3.8 | Quadratic Integrate-and-Fire Neuron | 80 |
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| Review of Important Concepts | 82 |
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| Bibliographical Notes | 83 |
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| Exercises | 83 |
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| 4. | Two-Dimensional Systems | 89 |
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| 4.1 | Planar Vector Fields | 89 |
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| 4.1.1 | Nullclines | 92 |
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| 4.1.2 | Trajectories | 94 |
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| 4.1.3 | Limit Cycles | 96 |
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| 4.1.4 | Relaxation Oscillators | 98 |
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| 4.2 | Equilibria | 99 |
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| 4.2.1 | Stability | 100 |
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| 4.2.2 | Local Linear Analysis | 101 |
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| 4.2.3 | Eigenvalues and Eigenvectors | 102 |
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| 4.2.4 | Local Equivalence | 103 |
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| 4.2.5 | Classification of Equilibria | 103 |
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| 4.2.6 | Example: FitzHugh-Nagumo Model | 106 |
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| 4.3 | Phase Portraits | 108 |
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| 4.3.1 | Bistability and Attraction Domains | 108 |
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| 4.3.2 | Stable/Unstable Manifolds | 109 |
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| 4.3.3 | Homoclinic/Heteroclinic Trajectories | 111 |
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| 4.3.4 | Saddle-Node Bifurcation | 113 |
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| 4.3.5 | Andronov-Hopf Bifurcation | 116 |
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| Review of Important Concepts | 121 |
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| Bibliographical Notes | 122 |
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| Exercises | 122 |
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| 5. | Conductance-Based Models and Their Reductions | 127 |
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| 5.1 | Minimal Models | 127 |
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| 5.1.1 | Amplifying and Resonant Gating Variables | 129 |
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| 5.1.2 | INa,p+IK -Model | 132 |
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| 5.1.3 | INa,t -Model | 133 |
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| 5.1.4 | INa, p+Ih -Model | 136 |
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| 5.1.5 | Ih+IKir -Model | 138 |
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| 5.1.6 | IK+IKir -Model | 140 |
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| 5.1.7 | IA -Model | 142 |
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| 5.1.8 | Ca2+ -Gated Minimal Models | 147 |
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| 5.2 | Reduction of Multidimensional Models | 147 |
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| 5.2.1 | Hodgkin-Huxley model | 147 |
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| 5.2.2 | Equivalent Potentials | 151 |
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| 5.2.3 | Nullclines and I-V Relations | 151 |
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| 5.2.4 | Reduction to Simple Model | 153 |
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| Review of Important Concepts | 156 |
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| Bibliographical Notes | 156 |
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| Exercises | 157 |
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| 6. | Bifurcations | 159 |
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| 6.1 | Equilibrium (Rest State) | 159 |
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| 6.1.1 | Saddle-Node (Fold) | 162 |
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| 6.1.2 | Saddle-Node on Invariant Circle | 164 |
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| 6.1.3 | Supercritical Andronov-Hopf | 168 |
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| 6.1.4 | Subcritical Andronov-Hopf | 174 |
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| 6.2 | Limit Cycle (Spiking State) | 178 |
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| 6.2.1 | Saddle-Node on Invariant Circle | 180 |
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| 6.2.2 | Supercritical Andronov-Hopf | 181 |
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| 6.2.3 | Fold Limit Cycle | 181 |
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| 6.2.4 | Homoclinic | 185 |
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| 6.3 | Other Interesting Cases | 190 |
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| 6.3.1 | Three-Dimensional Phase Space | 190 |
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| 6.3.2 | Cusp and Pitchfork | 192 |
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| 6.3.3 | Bogdanov-Takens | 194 |
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| 6.3.4 | Relaxation Oscillators and Canards | 198 |
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| 6.3.5 | Bautin | 200 |
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| 6.3.6 | Saddle-Node Homoclinic Orbit | 201 |
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| 6.3.7 | Hard and Soft Loss of Stability | 204 |
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| Bibliographical Notes | 205 |
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| Exercises | 210 |
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| 7. | Neuronal Excitability | 215 |
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| 7.1 | Excitability | 215 |
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| 7.1.1 | Bifurcations | 216 |
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| 7.1.2 | Hodgkin's Classification | 218 |
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| 7.1.3 | Classes 1 and 2 | 221 |
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| 7.1.4 | Class 3 | 222 |
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| 7.1.5 | Ramps, Steps, and Shocks | 224 |
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| 7.1.6 | Bistability | 226 |
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| 7.1.7 | Class 1 and 2 Spiking | 228 |
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| 7.2 | Integrators vs. Resonators | 229 |
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| 7.2.1 | Fast Subthreshold Oscillations | 230 |
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| 7.2.2 | Frequency Preference and Resonance | 232 |
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| 7.2.3 | Frequency Preference in Vivo | 237 |
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| 7.2.4 | Thresholds and Action Potentials | 238 |
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| 7.2.5 | Threshold Manifolds | 240 |
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| 7.2.6 | Rheobase | 242 |
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| 7.2.7 | Postinhibitory Spike | 242 |
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| 7.2.8 | Inhibition-Induced Spiking | 244 |
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| 7.2.9 | Spike Latency | 246 |
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| 7.2.10 | Flipping from an Integrator to a Resonator | 248 |
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| 7.2.11 | Transition Between Integrators and Resonators | 251 |
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| 7.3 | Slow Modulation | 252 |
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| 7.3.1 | Spike Frequency Modulation | 255 |
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| 7.3.2 | I-V Relation | 256 |
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| 7.3.3 | Slow Subthreshold Oscillation | 258 |
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| 7.3.4 | Rebound Response and Voltage Sag | 259 |
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| 7.3.5 | AHP and ADP | 260 |
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| Review of Important Concepts | 264 |
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| Bibliographical Notes | 264 |
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| Exercises | 265 |
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| 8. | Simple Models | 267 |
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| 8.1 | Simplest Models | 267 |
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| 8.1.1 | Integrate-and-Fire | 268 |
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| 8.1.2 | Resonate-and-Fire | 269 |
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| 8.1.3 | Quadratic Integrate-and-Fire | 270 |
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| 8.1.4 | Simple Model of Choice | 272 |
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| 8.1.5 | Canonical Models | 278 |
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| 8.2 | Cortex | 281 |
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| 8.2.1 | Regular Spiking (RS) Neurons | 282 |
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| 8.2.2 | Intrinsically Bursting (IB) Neurons | 288 |
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| 8.2.3 | Multi-Compartment Dendritic Tree | 292 |
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| 8.2.4 | Chattering (CH) Neurons | 294 |
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| 8.2.5 | Low-Threshold Spiking (LTS) Interneurons | 296 |
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| 8.2.6 | Fast Spiking (FS) Interneurons | 298 |
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| 8.2.7 | Late Spiking (LS) Interneurons | 300 |
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| 8.2.8 | Diversity of Inhibitory Interneurons | 301 |
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| 8.3 | Thalamus | 304 |
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| 8.3.1 | Thalamocortical (TC) Relay Neurons | 305 |
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| 8.3.2 | Reticular Thalamic Nucleus (RTN) Neurons | 306 |
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| 8.3.3 | Thalamic Interneurons | 308 |
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| 8.4 | Other Interesting Cases | 308 |
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| 8.4.1 | Hippocampal CA1 Pyramidal Neurons | 308 |
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| 8.4.2 | Spiny Projection Neurons of Neostriatum and Basal Ganglia | 311 |
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| 8.4.3 | Mesencephalic V Neurons of Brainstream | 313 |
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| 8.4.4 | Stellate Cells of Entorhinal Cortex | 314 |
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| 8.4.5 | Mital Neurons of the Olfactory Bulb | 316 |
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| Review of Important Concepts | 319 |
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| Bibliographical Notes | 319 |
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| Exercises | 321 |
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| 9. | Bursting | 325 |
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| 9.1 | Electrophysiology | 325 |
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| 9.1.1 | Example: The INa,p+IK+IK(M)-Model | 327 |
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| 9.1.2 | Fast-Slow Dynamics | 329 |
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| 9.1.3 | Minimal Models | 332 |
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| 9.1.4 | Central Pattern Generators and Half-Center Oscillators | 334 |
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| 9.2 | Geometry | 335 |
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| 9.2.1 | Fast-Slow Bursters | 336 |
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| 9.2.2 | Phase Portraits | 336 |
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| 9.2.3 | Averaging | 339 |
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| 9.2.4 | Equivalent Voltage | 341 |
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| 9.2.5 | Hysteresis Loops and Slow Waves | 342 |
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| 9.2.6 | Bifurcations "Resting <--> Bursting <--> Tonic Spiking" | 344 |
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| 9.3 | Classification | 347 |
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| 9.3.1 | Fold/Homoclinic | 350 |
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| 9.3.2 | Circle/Circle | 354 |
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| 9.3.4 | Fold/Fold Cycle | 364 |
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| 9.3.5 | Fold/Hopf | 365 |
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| 9.3.6 | Fold/Circle | 366 |
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| 9.4 | Neurocomputational Properties | 367 |
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| 9.4.1 | How to Distinguish? | 367 |
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| 9.4.2 | Integrators vs. Resonators | 368 |
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| 9.4.3 | Bistability | 368 |
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| 9.4.4 | Bursts as a Unit of Neuronal Information | 371 |
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| 9.4.5 | Chirps | 372 |
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| 9.4.6 | Synchronization | 373 |
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| Review of Important Concepts | 375 |
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| Bibliographical Notes | 376 |
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| Exercises | 378 |
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| 10. | Synchronization | 385 |
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| Solutions to Exercises | 387 |
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| References | 419 |
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| Index | 435 |
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| Synchronization (www.izhikevich.com) | 443 |
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| 10.1 | Pulsed Coupling | 444 |
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| 10.1.1 | Phase of Oscillation | 444 |
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| 10.1.2 | Isochrons | 445 |
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| 10.1.3 | PRC | 446 |
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| 10.1.4 | Type 0 and Type 1 Phase Response | 450 |
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| 10.1.5 | Poincare Phase Map | 452 |
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| 10.1.6 | Fixed Points | 453 |
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| 10.1.7 | Synchronization | 454 |
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| 10.1.8 | Phase-Locking | 456 |
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| 10.1.9 | Arnold Tongues | 456 |
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| 10.2 | Weak Coupling | 458 |
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| 10.2.1 | Winfree's Approach | 459 |
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| 10.2.2 | Kuramoto's Approach | 460 |
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| 10.2.3 | Malkin's Approach | 461 |
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| 10.2.4 | Measuring PRCs Experimentally | 462 |
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| 10.2.5 | Phase Model for Coupled Oscillators | 465 |
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| 10.3 | Synchronization | 467 |
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| 10.3.1 | Two Oscillators | 469 |
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| 10.3.2 | Chains | 471 |
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| 10.3.3 | Networks | 473 |
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| 10.3.4 | Mean-Field Approximations | 474 |
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| 10.4 | Examples | 475 |
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| 10.4.1 | Phase Oscillators | 475 |
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| 10.4.2 | SNIC Oscillators | 477 |
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| 10.4.3 | Homoclinic Oscillators | 482 |
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| 10.4.4 | Relaxation Oscillators and FTM | 484 |
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| 10.4.5 | Bursting Oscillators | 486 |
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| Review of Important Concepts | 488 |
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| Bibliographical Notes | 489 |
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| Solutions | 497 |
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